I agree with psimiet2001 for the most part, although 3x is usually overdoing it on a 28h wheel. 2x will be the closest to tangential without going over (which can cause stress at the flange). The rest of the components are a trade-off. Velocity Aerohead rims will be a tad lighter but not as durable as the DT RR. For other builders, I've heard a lot of good things on this board about Mike Garcia
www.oddsandendos.com Check out their Niobium30 rim, which is more aero at a small weight penalty,